Long, Strange Trips

The last quarter-century in planetary exploration has stretched the limits of human imagination: the banner image of the Venera footpad on our sister planet, Venus, illustrates the challenges and rewards of reaching out in our solar neighborhood. The crusty surface just below that circularly-spiked footprint is hot enough to melt lead.

Even fewer may recognize that international teams have flown a balloon in the clouds on Venus, or touched down on an asteroid. Missions have intentionally crashed a spacecraft into the moon, in hopes of observing from Earth an ejected spray of lunar ice. In a spectacular planetary-scale catastrophe, orbiting telescopes have witnessed comets smash into Jupiter. A steady meteor stream has been found identifiably reaching Earth from Mars, Venus and the moon– many of which land on Antarctic fields with their interior temperatures never having exceeded one hundred degrees. Mars alone contributes fifteen annually.

More than four and half million home computers have been tied together, in hopes of detecting an intelligent radio signal from another planet. Their total computer processing units have combined what would take a single computer more than one and half million years to complete. A collosal asteroid strike on Earth has been proposed as what killed the dinosaurs. The moon itself has been modelled as originating from another terrestrial impact. In excess of one hundred planets have been found outside our solar system. Water-ice has been found on martian polar caps. A remote control rover has navigated safely between sharp martian boulders, while being driven from millions of miles away. Thick sheets of ice may cover an ocean on Jupiter’s moon, Europa. The catalog of nearby habitable stars has tallied more than 17,000 candidates. Massive stars so dense that they represent a new kind of matter–so-called quark stars–populate the universe with exotic sub-atomic physics.

The quarter-century’s timeline, by mission, year, and spacecraft, are highlighted in summary below with links to more information.

As this month begins an unprecedented blitz on Mars, including the first time that multiple landers will operate at the same time since 1977, the future of planetary exploration is also worth anticipating. Even more ambitious missions will attempt to land on a comet. A probe will try to land on Saturn’s moon, Titan–the smoggy moon with a rich atmosphere almost as thick as Earth’s. Many international returns to Mars are anticipated after the January 2004 landing assault, including intelligent rovers pre-programmed for hazard avoidance. The encyclopedic cataloguing of new planets will get help from new telescopes, ones specifically trying to image distant stars that dim as their comparatively dark and tiny planets transit and eclipse the light reaching us. Both fiery Mercury and frigid Pluto will become foci of new missions. Samples of solar wind and comet dust may be returned to Earth. New techniques for projectile sampling, where bullets are fired into the moon, Europa, and comets will complement the traditional land-and-scoop methods pioneered by Viking on Mars. New landing methods will extend the controlled collisions of airbag bounces in hopes of more accurate positioning and deployments. New solar-powered, ion engines will make the most of the least–charged particles provide fuel to go further at less cost than explosive chemical drives.

Astrobiology Magazine congratulates and commemorates those who have imagined what the surface of Venus might look like up-close, and wanted to drive a car on Mars.

The icy cracks of Jupiter’s moon Europa continue to intrigue astrobiologists. The white sheen is likely frost and the moon’s heat source is a combination of an underground ocean and tidal heating under the strong gravitational pull of Jupiter. Credit: Galileo Project, JPL, NASA

What’s Next

2004 - European Rosetta mission, to land a science probe on the surface of Comet Churyumov-Gerasimenko
– Mercury orbiter, MESSENGER, to look for water-ice on the closest planet to the Sun
– Comet rendezvous, Deep Impact, to fire a bullet into comet P/Tempel 1 and study the ejecta and crater
– Japanese Lunar-A, Lunar Mapping Orbiter and Penetrator, to fire two bullets 3 meters into the lunar soil near Apollo 12 and 14 sites